Magnetic tripping devices for electrical switching devices are essentially known. In a classical embodiment of a magnetic tripping device, this includes, in particular, three parts, namely a yoke, a hinged armature and a hinged armature spring. The hinged armature is pre-tensioned by the hinged armature spring. A current, which flows through a conductor or current path guided in the yoke, induces a magnetic field in the yoke and in the hinged armature.
The magnetic field exerts a force on the hinged armature in the air gap between the hinged armature and the yoke, which counteracts in particular at least part of the spring force. Once the current and thus the magnetic field induced thereby in the yoke exceeds a specific strength, the force of the magnetic field on the hinged armature also exceeds the spring force, thereby drawing the hinged armature toward the yoke. This may be caused in particular by a current peak, such as occurs in the event of a short-circuit. The yoke and the hinged armature thus form a magnetic circuit.
In the process, the hinged armature interrupts the power circuit, especially for example by way of a downstream mechanism. In order to be able to execute the afore-described movement, the hinged armature is mounted in a hinged armature bearing. In such cases the bearing has an influence on the precision with which the current can be set when the magnetic tripping devices trip. A bearing in which the hinged armature firstly executes a linear sliding movement and in particular not immediately a pivoting movement when the magnetic field in the hinged armature bearing is increasing, results in a reduction in the precision of the tripping current.
DE 38 80 055 T2 discloses a magnetic tripping device. With this magnetic tripping device, a retaining element is also provided on the hinged armature, which is hinged on a plate attached as an additional element on the yoke. As a result, a defined contact surface and therewith a defined support of the hinged armature can be achieved. The embodiment with additional components nevertheless renders these magnetic tripping devices costly and complicated in terms of assembly.